Insert for changing the compression ratio of internal-combustion engines



91 6k. 26, 1948. HOLLINGSWORTH 2,452,238

INSERT FOR CHANGING THE COMPRESSION RATIO OF INTERNAL-COMBUSTION ENGINES Filed Jan. 7, 1948 INVEN TOR, flollingswwwz Patented Oct. 26, 1948 INSERT FOR CHANGING THE COMPRESSION RATIO OF INTERNAL-COMBUSTION EN- (nuns Raphael Hollingsworth, Hedrick, Iowa Application January 7, 1948, Serial No. 901

2 Claims.

Certain types of commercial farm tractors are equipped with low compression engines in which the outer ends of the inner peripheral surfaces of the cylinders are formed with annular recesses or cutaway portions to facilitate the assembly within the cylinders of usual conventional pistons provided with piston rings. These engines are generally satisfactory in operation but with the advent of high octane gasoline it has been found that their efficiency and economy is improved by increasing their compression pressure. It is an object of this invention, therefore, to provide an improved cylinder insert for increasing the compression pressure in engines of this type.

A further object of this invention is to provide an insert for an engine cylinder which is of a simple construction, adapted to be quickly and easily assembled within the cylinder without the use of any independent or specially provided fastening means, and capable of increasing the op- 'end of the recess, is tapered inwardly and then terminates in a straight section so that the thickness of the insert over its full axial length is greater than the depth of the recess transversely of the cylinder. The insert is positively maintained within the cylinder against axial movement by being clamped between the cylinder head member and the inner end of the recess.

Further Objects, features and advantages of this invention will become apparent from the following description when taken in connection with the accompanying drawings, in which:

Fig.' l is a fragmentary longitudinal sectional view of an engine showing the cylinder and piston structure thereof in assembly relation with the insert of this invention; and

Fig. 2 is an enlarged perspective view of the insert.

With reference to the drawings, there is illustrated in Fig. 1 a cylinder 5 of an internal combustion engine having an associated piston 6. A

z cylinder head 1, secured against the outer end portion 8 of the cylinder by screws or the like 9. is provided with an intake valve II, and an exhaust valve 12 of conventional poppet type and opening into the outer end of the cylinder. A usual spark plug (not shown) initiates combustion of the fuel admitted to the cylinder by the intake valve H, .with combustion taking place within the outer end portion 8 of the cylinder.

Formed at theouter end portion f the cylinder, and within the inner peripheral surface l8 thereof, is an annular recess or cutaway portion M, the inner end wall I5 01 which defines an annular shoulder which extends completely about the inner peripheral surface of the cylinder. The opposite end of the recess is open to the outer end 16 of the cylinder.

This recess is provided in many types of engines to facilitate the assembly of the pistonfi within the cylinder 5. In other words, when the piston rings I! are initially positioned about the piston, they project radially outwardly from the piston. By virtue of the recess Hi, the rings [1, on movementof the piston 6 inwardly of the accommodated within the recess, and on a continued inward movement of the piston 6 are moved within the confines of the piston concurrently with their movement over the shoulder l5 which generally is of a tapered construction as illustrated in Fig. 1'. In the operation of the engine, the outward limit of travel of the piston 6 is restricted so that its head end It! is always at a position inwardly of the shoulder l5.

The insert of this invention, indicated generally as 20, is of an annular or ring shape having its outer peripheral surface 2| of a straight cylindrical contour. The inner peripheral surface of the insert is formed with a tapered section 22 and a straight section 23, the junction 24 of which sections occurs at a position substantially midway between the ends of the insert. The section 22, as best appears in Fig. 1, tapers inwardly of the insert from the insert end 26, which is formed so as to fit in abutting engagement against the reacsasae thickness of the insert is greater than the depth of the recess, whereby the inner peripheral surface of the insert is located entirely within the confines of the inner peripheral surface II of the cylinder.

In the assembly of the insert 20 within the cylinder 5, it is only necessary to remove the cylinder head I. The insert, with its end I! in a leading position, is then inserted within the recess through the outer end of the cylinder 5, to a position defined by the abutting engagement of its end 28 with the shoulder II. At this position of the insert 20, its end 21 is substantially flush with the outer end surface l6 of the cylinder 8.

As a result, on assembly 'of the cylinder head 1 with the cylinder 5, the clamping action of the screws 8 provides for the insert beingpositively clamped against movement axially of the cylinder. between the shoulder l and the cylinder head.

By virtue of this assembly of the insert within the cylinder, the compression pressure of the cylinder is increased by an amount corresponding to the space within the cylinder occupied by the insert. Further, it has been found that the tapered section 22 of the insert provides for an increased .turbulence and agitation of the ccmbustible mixture admitted to the cylinder, which acts to improve the firing and burning of the mixture.

From a consideration of the above description, it is seen that the invention provides an improved insert which is of a simple one-piece construction and readily adapted for application to many types of cylinder constructions without requiring any machine work on the cylinder. Further, the insort is maintained in assembly position within the cylinder between the recess end wall I! and the cylinder head 1. so as to eliminate entirely the need of any specially provided fastening means.

Although the invention has been described with respect to a preferred embodiment thereof, it is to be understood that it is not to be so limited since changes can be made therein which are within the full intended scope of this invention as defined by the appended claims.

1. In an internal combustion engine including a cylinder and a piston therefor, with the inner peripheral surface at the outer end of the cylinder being formed with an annular recess the inner end of which constitutes an annular shoulder, an annular insert for said cylinder receivable in said recess and of a construction such that one of its ends is in abutting engagement with said shoulder and its other end is substantially flush with the outer end of the cylinder, with the inner peripheral surface of said insert having a first p rtion tapered inwardly from said one end thereof to a position substantially midway between its ends, and a second portion of a straight contour continued from said tapered portion to the other end of said insert, whereby said inner peripheral surface is arranged entirely within the confines of the inner peripheral surface of said cylinder, a head member for said cylinder engageable with the other end of said insert, and means for clampins said head member on said cylinder, with said insert being held between said shoulder and head member against axial movement relative to said cylinder.

2. An insert for the cylinder of an internal combustion engine having a head member and the outer end of its inner peripheral surface formed with a recess the outer end of which is open to the outer end of the cylinder, and the inner end of which constitutes an annular shoulder on said surface, said insert being of an annular shape and constructed so as to be received within said recess between said shoulder and head member, with the inner peripheral surface of said insert having a REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,173,111 Kelly Feb. 22, 1916 1,331,911 Guy Feb. 24, 1920 1,520,353 Kavanaugh Dec. 23, 1924 1,623,940

Mader Apr. 5, 1927 

